One in five Americans over the age of 75 years (~4 million Americans) has type 2 diabetes and this population is expected to double over the next 25 years. These oldest patients have the highest rates of complications, geriatric conditions, adverse drug events and death, and yet evidence to guide their care is lacking. Despite the lack of evidence, over 50% of the oldest patients continue to receive intensive glucose- lowering treatment, irrespective of health status. Recent guidelines agree that care should be individualized, but lack specificity and are often conflicting. We lack an adequate understanding of how the oldest patients' barriers to self-management and treatment preferences align with medication use and impact safety-related outcomes. Current guidelines endorse the use of life expectancy for setting targets, but more readily identified characteristics, such as organ dysfunction, dementia or diabetes duration, may be just as useful for individualizing treatment. Additionally, it is unclear how changes in treatment intensity may impact safety- and diabetes-related outcomes and healthcare utilization. Our objective is to evaluate diabetes management strategies that have clinical equipoise and controversy for our oldest patients with type 2 diabetes. We will conduct a survey among 3000 of the oldest patients with diabetes and their caregivers regarding barriers and preferences for care. We will link survey responses to robust clinical care data from a well-characterized, diverse population of 52,725 diabetes patients, ages ? 75 years: AIM 1: We will survey patients and caregivers regarding i) self-management barriers (e.g. financial barriers, poor functional status, inadequate health literacy) and ii) treatment preferences (e.g. for intensification, de-intensification) and evaluate to what extent barriers and preferences are associated with medication use (e.g., adherence, prescribing), and safety-related outcomes (e.g., hypoglycemia, falls). AIM 2: We will study variation in diabetes care, safety- and diabetes-related outcomes (hypoglycemia, complications, mortality) and healthcare utilization for specific risk groups (advanced kidney disease, heart failure, dementia, late onset diabetes). AIM 3: Among patients with A1C<7.5%, we will compare the impact of de-intensification vs. maintenance vs. intensification of therapy on safety- and diabetes-related outcomes and healthcare utilization. AIM 4: We will study the choice of medications used for intensifying treatment on safety- and diabetes-related outcomes and healthcare utilization after accounting for baseline glycemic control and treatments. Completion of these aims will elucidate the consequences of current medical decision-making and inform future guidelines for the oldest patients with diabetes.